In comunications systems, it is well known to use modular plugs and jacks to establish connections. Modular plugs each include a plurality of blade-like terminals having tangs which engage electrically conductors of a cord end that is secured within a housing of the plug. Modular jacks each include a plurality of wire-like contact elements to each of which is connected an insulated conductor and a cavity for receiving a plug with retroflexed end portions of the contact elements being disposed in the cavity to engage the terminals of the plug inserted into the cavity.
A well known adapter includes a housing having a plug end and a jack end which includes two stacked jack cavities. See U.S. Pat. No. 4,241,974 which issued on Dec. 30, 1980, in the name of E. C. Hardesty and which is incorporated by reference hereinto. Metallic contact elements extend from one jack cavity to the plug end, which is adapted to be received in a wall jack for example, and to the other jack cavity. Each end portion of each contact element in a jack cavity is retroflexed to engage electrically a terminal of a plug which is inserted into that jack cavity.
In one variation of the above described adapter, it becomes necessary to have one of the jack cavities adapted to receive a plug having communications terminals and to have the other jack cavity adapted to receive a plug which provides low voltage power, for example, to the adapter. Connections must be made between the communications terminals of the plug in the one jack cavity to the wall jack and between power terminals of the plug in the one jack cavity and the power-supplying plug in the other cavity. Typically this variation involves only a few connections which must be made from the one jack cavity to the other jack cavity but a plurality which must be made from the one jack cavity into the plug end to establish communications paths between it and the wall jack.
This capability has been provided by an adapter having a housing which includes two side by side jack cavities and a plug end. It includes eight contact element end portions which are disposed in one of the jack cavities and six end portions in the plug end. For power, two contact element portions are provided in the other jack cavity. Harness type wiring which includes insulated conductors is used to connect six of the metallic contact portions in the one jack cavity with the six metallic contact portions in the plug end. Such wiring also is used to connect two of the metallic contact portions in the one jack cavity to the two metallic contact portions in the other jack cavity. Although, this adapter provides the needed capability, it involves harness wiring which is relatively expensive. Clearly, there is a need to provide an adapter which provides the same capability within existing dimensional constraints but one which does not involve harness type wiring.
Adapters involving contact element communications paths without harness wiring are known. For example, see the adapter disclosed in priorly mentioned U.S. Pat. No. 4,241,974 which was intended to replace a side-by-side jack cavity adapter. Another example of a modular device having end-to-end contact elements is that shown in U.S. Pat. No. 4,488,355 which issued on Dec. 18, 1984 in the names of E. M. Hutchins et al.
In each of the last-described modular adapters, the contact elements are assembled to the housing and their end portions formed into retroflexed configurations by automatic assembly apparatus. See also application Ser. No. 645,182 which was filed on Aug. 29, 1984 in the name of E. M. Hutchins. Wires are positioned in the housing with end portions disposed in an array in each jack cavity. Tooling is inserted into each cavity to engage the array of wire ends and to curl them about a lip to direct them inwardly into the cavity. This presents no problems in a six conductor jack cavity inasmuch as there are no obstructions to the bending of the wire ends. However, in going to eight conductors in a jack cavity, the outermost conductors cannot be formed with a retroflexed end portion with the presently used housing.
The presently used housing includes a jack opening which is designed to accommodate a modular plug. Accordingly, it has a center opening designed to receive a locking tab of the plug, and side portions which depend from a ceiling and which are spaced apart a distance sufficient to receive a locking tab of a plug therebetween. The width of the locking tab and its shoulders for both six and eight conductor modular plugs is the same. However, if the jack cavity of the present design adapter were to be enlarged to receive eight contact elements and retain the same distance between the side depending portions, curling of the outermost contact element end portions on each side of the jack cavity cannot be accomplished in place. Obstructions formed by the side ceiling portions of the jack cavity inhibit turning of the end portions of the outermost contact elements.
What is needed and what is not provided by the prior art is a modular adapter which includes a housing with which are assembled easily several contact elements that extend between one jack cavity and another and a plurality of contact elements which extend from the one jack cavity to a plug end. Further, the arrangement of housing and contact elements must be such that the end portions of all the contact elements may be formed easily into retroflexed configurations after having been inserted into the housing.